It's new TNGA platform will also allow for 20 percent less vehicle weight

Toyota Motor Corp. is shedding more light on the upcoming fourth-generation Toyota Prius, including a whole new design and at least an 8 percent gain in fuel economy.

According to Automotive News, Toyota is looking to make some major changes in design, manufacturing and technology for the next Prius, which is due to be released in a year.

For starters, the next-gen Prius will be the first (or one of the first) Toyota vehicles based on the automaker's latest platform, "Toyota New Global Architecture" (TNGA). TNGA aims to improved engineering and low-cost as well as flexible manufacturing.

This platform will call for a major redesign of the Prius' looks. TNGA means lower-slung vehicles with a more planted stance and lower center of gravity, which should improve handling and offer a sportier look.

One possible design direction for the next generation Prius -- the FT-Bh concept

Chris Hostetter, Toyota's vice president for strategic planning in the U.S., has said that the Prius could use a new look.

"There's an undercurrent among most people that they're ready for a new Prius look," said Hostetter. "Maybe our architecture has been a little bit similar for the last two generations."

The Prius, which was first launched in Japan in 1997 and the U.S. in 2000, had an exterior design that was altered from Toyota's Yaris sedan. The second-generation Prius was released in 2003, and it received the raked hood and windshield. From 2003 to 2004, Prius sales increased dramatically from 43,162 to 125,742. Toyota is likely hoping to do the same with a completely redesigned fourth-generation Prius.

Aside from design, the new Prius is getting a makeover under the hood. Its new ultra-efficient gasoline engine will achieve thermal efficiency rates above 40 percent, which is a nice boost from 38.5 percent in the current Prius.

Toyota also talked batteries in its latest Prius revelations. It’s deciding whether to use lithium ion batteries for its fourth-generation Prius, or to offer some models with lithium ion and others with nickel-metal hydride batteries. While Toyota likes the power and energy performance of lithium ion, it worries about the cost compared to nickel-metal hydride batteries.

Satoshi Ogiso, managing officer in charge of global product planning at Toyota, said the automaker is pushing for at least an 8 percent improvement in fuel economy, which is slightly less than the 10 percent gains each Prius before it has received.

"Generally speaking, hybrid powertrains are more mature than before. So, the general tendency is that when a technology matures, the improvement ratio is saturating, dropping," said Ogiso. "We will do our best effort to keep that pace."

But the fact that TNGA models will cut vehicle weight will be helpful. It was reported that Toyota should be able to cut overall vehicle weight by up to 20 percent on TNGA models, which includes the new Prius.

Toyota mentioned lighter components, such as its new one-size-fits-all heating and air-conditioning unit that 20 percent smaller than the previous Prius generation's.

Jonny Lieberman, senior features editor at Motor Trend, recently spoke with his sources at Toyota and shared a bit of secret info about the next Prius. Lieberman hinted that the next Prius would have a fuel economy rating of 60 mpg. This shouldn't be too hard to achieve assuming a lighter vehicle weight, more powerful electric motor, and a possible switch from NiMH to lithium-ion batteries.

No, the price in the US is seasonal. Diesel is cheaper than gasoline in summer, and more expensive in winter. It's supply and demand. Diesel fuel is the same thing as home heating oil - the only difference is the additives and the taxes.

Either way, paying 10% more for a 30% gain means you come out way ahead when you drive a diesel.

Not true, diesels are well known for their longevity and durability. The parts you mention are rated for many hundreds of thousands of miles. 18 wheeler trucks go 1 Million miles or more between engine overhauls. Sure the parts cost more, but if they don't need service until after 200k miles, you're still coming out ahead.

3) Diesels get marginal city fuel economy, which is increasingly more important

Not true, the diesel cycle is considerably more efficient in the city than the otto gasoline cycle. The reason is otto cycle only works in a narrow air/fuel ratio range. So it *must* inject a certain quantity of fuel for a given quantity of air. I.e. gasoline engines burn a lot of fuel even just idling.

Diesels on the other hand are not constrained by fuel mixture ratio. They can run as lean as 80:1 which means fuel consumption while idling is miniscule. Furthermore, diesels run *cleaner* the leaner the mixture is, so at idle, a diesel is polluting considerably less than a gasoline engine.

Is this a joke? It's not even close. Otto cycle on the most efficient gasoline engines is ~34%. Diesel on the other hand is 40% or more. This is a big difference! Diesel is way more efficient and always has been. Diesel-electric locomotives have achieved 50% efficiency even, a world record for internal combustion engine efficiency. Gasoline engines will be stuck in the low 30% range forever.

5) Your 1979 Rabbit would be considered a death trap today

Don't confuse the issue with this strawman. We're talking MPG's here. This new Pious will be considered a "death trap" 30 years from now. So what?

6) The only 3L/100km cars in Europe were the Lupo and A2. Both were failures.

Nonsense. The point is they were commercially available. Also ~50 MPG is pretty standard for small diesel cars in Europe, while here in the US 50 mpg is considered top of the range for MPG.

Nonsense. It sells primarily on image. Vain leftists who want to put on an image of "greenness", while ignoring the reality of the severe environmental impact of strip-mining for lithium. Also ignoring the real world economics of a car that needs a $5000 battery pack replacement every ~7 years.

8) The UK's "Greenest Cars" probably couldn't be sold in America due to emissions.

Rather than speculating, why don't you go look at the Euro5 and upcoming Euro6 emissions standards, and compare them to the US standards. Hint: the US standards are not more "strict".

I'm not going to get into your other comments, but this one stuck out to me:

quote: No, the price in the US is seasonal. Diesel is cheaper than gasoline in summer, and more expensive in winter. It's supply and demand. Diesel fuel is the same thing as home heating oil - the only difference is the additives and the taxes.

Where do you live? It has been YEARS since I've seen diesel priced LOWER than regular unleaded. Even in the summer time, diesel is at least 50c higher than regular unleaded in the Raleigh, NC area.

I manage to get my diesel premium down to 40c by using my Kroger rewards points at Shell and Kroger fuel stations.

Here in Ohio, Diesel rarely is ONLY 10% more than gasoline and typically it is 30% more. I started watching the difference because I was thinking of looking at a diesel vehicle and also figured the diesel offered roughly a 30% better fuel economy. Paying close to 30% more for the fuel effectively nullifies any net economic advantage of having a diesel engine.

1) In America, diesel is taxed at a higher rate and sold in lower volumes than gasoline. It's very rare to see diesel cost less than gasoline, at least where I've traveled.

2) Heavy-duty diesel engines have extreme longevity because they are under-stressed. An semi-truck diesel puts out ~30hp/L. A VW TDI engine puts out 70hp/L.

3) The Prius hybrid system makes up for the otto cycle deficiency. The Prius and VW TDI Sportwagen are comparably-sized/powered automobiles. Look at the EPA city ratings.

4) The Prius engine has a thermal efficiency of 38.5%. The next-gen engine should break 40%. The hybrid drive system also allows the Prius to operate near max-BSFC for longer periods of time than an automatic TDI diesel.

5) The 1979 Rabbit fuel economy rating is irrelevant since it can't meet modern safety standards. The 1986 CRX HF was rated well over 50mpg combined, but it's irrelevant because you can't build a CRX today.

6) They were available, but too expensive for the gain in efficiency. The Prius had the same problem when it came out, but was saved by government subsidies (which I never agreed with). Total cost of ownership is what matters.

7) This simply isn't true anymore. Also, the Prius battery pack has proven to be extremely reliable. The early Honda hybrids were notorious for eating batteries.

8) I'm not 100% sure, but diesel emissions are stricter in the USA, especially with regards to sulfur. Euro emissions are often modeled after CARB regulations.